Two sound sources emitting plane waves separated by 12 meter vibrates according to law y1=3cos4πt and y2=4sin4πt respectively. A point in the medium is at a position 8m from first source and 4m from second on the line joining two sources. The sources out waves of velocity 32 m/s. find equation of the motion of the particles (y1, y2are in centimeter and t is in second)  
A)  yR=5sin(4πt+tan−1(43))
B)  yR=−5sin(4πt+tan−1(34))
C)  yR=−5sin(4πt+tan−1(43))
D)  yR=5sin(4πt+tan−1(34